Materials such as metal or glass, sapphire, or other ceramics may be finished using a variety of different abrading or other material removal processes. For example, polishing may rub a surface of a part using a tool (such as a bristle brush) to achieve a particular surface finish. In many cases, polishing is performed on flat or planar surfaces using flat rotatory brushes. Such a process may work well for polishing flat surfaces, but may not create as uniform a polished finish for three-dimensional features.